4-bit shift register: build and simulate it online
Four D flip-flops in a chain: each clock moves every bit one place along.
Build the 4-bit shift register in the free online simulator — it checks your circuit automatically.
What you need
- 2 logic switches labelled DIN, CLK
- 4 probes labelled Q0, Q1, Q2, Q3
- 4 D flip-flops
Step by step
- Inputs and outputs. From the Logic section of the library, drop digital inputs (0/1 boxes) or logic switches for the inputs, and digital outputs or probes for the outputs; give each its label in the inspector (the checker finds them by label). Switches DIN, CLK; Probes Q0, Q1, Q2, Q3
- Four D flip-flops. All share CLK; DIN → D of the first; each Q → D of the next.
- Prove it. Shift in 1, 0, 1, 1 and watch it march along.
Expected sequence
| # | inputs | clock | Q0 | Q1 | Q2 | Q3 |
|---|---|---|---|---|---|---|
| 1 | DIN=1 | ↑ | 1 | 0 | 0 | 0 |
| 2 | DIN=0 | ↑ | 0 | 1 | 0 | 0 |
| 3 | DIN=1 | ↑ | 1 | 0 | 1 | 0 |
| 4 | DIN=1 | ↑ | 1 | 1 | 0 | 1 |
Frequently asked questions
How do you build a 4-bit shift register?
Four D flip-flops in a chain: each clock moves every bit one place along. In short: inputs and outputs, then four d flip-flops, then prove it.
How does a 4-bit shift register behave clock by clock?
It is checked over 4 steps: DIN=1, DIN=0, DIN=1, DIN=1. The table on this page shows the expected Q0, Q1, Q2, Q3 after each clock.
What parts do you need for a 4-bit shift register?
4 D flip-flops — plus logic switches for the inputs and probes for the outputs.
Can I simulate a 4-bit shift register online for free?
Yes. Open it in the BitForBytes Embedded Lab, a free browser-based circuit and logic simulator: drag in the gates, wire them, and press "Check my circuit" — every clock cycle is simulated and marked for you. No download or sign-up needed.
Part of DSD 34 · Shift registers in the free BitForBytes digital system design course.